Montenegro is a country in Southeast Europe, on the Balkan Peninsula. Its 25 municipalities have a total population of 633,158 people in an area of 13,883 km² (5,360 sq mi). It is bordered by Serbia to the northeast, Bosnia and Herzegovina to the northwest, Kosovo to the east, Albania to the southeast, and Croatia to the west, and has a coastline along the Adriatic Sea to the southwest. The capital and largest city is Podgorica, while Cetinje is the Old Royal Capital and cultural centre.

Before the arrival of the Slav peoples in the Balkans in the 6th and 7th centuries CE, the area now known as Montenegro was inhabited principally by people known as Illyrians. During the Early Medieval period, three principalities were located on the territory of modern-day Montenegro: Duklja, roughly corresponding to the southern half; Travunia, the west; and Rascia proper, the north. The Principality of Zeta emerged in the 14th and 15th centuries. From the late 14th century to the late 18th century, large parts of southern Montenegro were ruled by the Venetian Republic and incorporated into Venetian Albania. The name Montenegro was first used to refer to the country in the late 15th century. After falling under Ottoman Empire rule, Montenegro gained semi-autonomy in 1696 under the rule of the House of Petrović-Njegoš, first as a theocracy and later as a secular principality. Montenegro's independence was recognised by the Great Powers at the Congress of Berlin in 1878. In 1910, the country became a kingdom. After World War I, the kingdom became part of Yugoslavia. Following the breakup of Yugoslavia, the republics of Serbia and Montenegro together proclaimed a federation. In June 2006 Montenegro declared its independence following a referendum.

Montenegro has an upper-middle-income economy, mostly service-based, and is in late transition to a market economy. It is a member of the United Nations, NATO, the World Trade Organization, the Organization for Security and Co-operation in Europe, the Council of Europe, and the Central European Free Trade Agreement. Montenegro is also a founding member of the Union for the Mediterranean, and has been in the process of joining the European Union since 2012.

Montenegro's (/ˌmɒntɪˈniːɡroʊ, -ˈneɪɡroʊ, -ˈnɛɡroʊ/ ^ⓘ MON-tin-E(E)G-roh, -⁠AY-groh; Montenegrin: Crna Gora / Црна Гора; Albanian: Mali i Zi) English name derives from a Venetian calque of the Montenegrin phrase "Crna Gora", meaning literally "Black Mountain", deriving from the appearance of Mount Lovćen, which was covered in dense evergreen forests. Crna Gora was mentioned for the first time in edicts issued by Stefan Uroš I to the Serbian Orthodox Zeta Episcopate seat at Vranjina island in Lake Skadar. It came to denote the majority of contemporary Montenegro in the 15th century.

Modern-day Montenegro was more and more known by that name in the historical period following the fall of the Serbian Despotate in 1459. Originally, it had referred to only a small strip of land under the rule of the Paštrovići tribe, but the name eventually came to be used for the wider mountainous region after the Crnojević noble family took power in Upper Zeta. The aforementioned region became known as Stara Crna Gora 'Old Montenegro' by the 19th century to distinguish the independent region from the neighbouring Ottoman-occupied Montenegrin territory of Brda (the "Highlands"). Montenegro further increased its size several times by the 20th century, as the result of wars against the Ottoman Empire, which saw the annexation of Old Herzegovina and parts of Metohija and southern Raška. Its borders have changed little since then, losing Metohija and gaining the Bay of Kotor.

After the second session of the AVNOJ during World War II in Yugoslavia, the contemporary modern state of Montenegro was founded as the Federal State of Montenegro (Montenegrin: Савезна држава Црне Горе / Savezna država Crne Gore) on 15 November 1943 within the Yugoslav Federation by the ZAVNOCGB. After the war, Montenegro became a republic under its name, the People's Republic of Montenegro (Montenegrin: Народна Република Црна Гора / Narodna Republika Crna Gora) on 29 November 1945. In 1963, it was renamed to the Socialist Republic of Montenegro (Montenegrin: Социјалистичка Република Црна Гора / Socijalistička Republika Crna Gora). As the breakup of Yugoslavia occurred, the SRCG was renamed to the Republic of Montenegro (Montenegrin: Република Црна Гора / Republika Crna Gora) on 27 April 1992 within the Federal Republic of Yugoslavia by removing the adjective "socialist" from the republic's title. Since 22 October 2007, a year after its independence, the name of the country became simply known as Montenegro. The country is known as Mali i Zi (lit. black mountain) in Albanian, while it is known as Crna Gora in Montenegrin, Serbian, Bosnian, and Croatian.

Modern-day Montenegro was part of Illyria and populated by the Indo-European-speaking Illyrians. The Illyrian kingdom was conquered by the Roman Republic in the Illyro-Roman Wars and the region was incorporated into the province of Illyricum (later Dalmatia and Praevalitana).

Three principalities were located on the territory: Duklja, roughly corresponding to the southern half, Travunia, the west, and Raška, the north. Duklja gained its independence from the Byzantine Roman Empire in 1042. Over the next few decades, it expanded its territory to neighbouring Rascia and Bosnia, and also became recognised as a kingdom. Its power started declining at the beginning of the 12th century. After King Bodin's death (in 1101 or 1108), civil wars ensued. Duklja reached its zenith under Vojislav's son, Mihailo (1046–1081), and his grandson Constantine Bodin (1081–1101).